1. Field of the Invention
The present invention relates to compounds of formula (I) which have excellent antibacterial activity and pharmaceutically acceptable derivatives or pharmaceutically acceptable salts thereof.
The present invention also relates to a composition effective to prevent or treat bacterial infections comprising a compound described above as an active ingredient.
The present invention further includes the use of a compound described above in order to prepare a medicament effective to prevent or treat bacterial infections.
The present invention is concerned with a method effective to prevent or treat bacterial infections in warm-blooded animals which comprises administering to them a pharmacologically effective amount of a compound described above.
2. Background Information
b-lactam antibiotics, amino-glycosides, quinolone carboxylic acids, isoniazids and rifampicin have conventionally been used in the treatment and prophylaxis of bacterial infections. Recently a lot of bacteria have become resistant to these antibiotics. It is desirable to develop new compounds which have different types of mechanism of antimicrobial action from the conventional ones.
On the other hand, it has been known that capuramycin, having the formula shown below, exhibits anti acid-fast bacillus activity without cross-resistance to conventional medicaments. However, its antibacterial activity is not potent enough to enable its use as an antibacterial agent. (J. Antibiotics, 29, (8), 1047–1053 (1986)).

After many compounds were prepared by chemical modification of capuramycin, the present inventors made intensive studies on their pharmacological activities for several years. As a result, they have found that compounds of formula (I), pharmaceutically acceptable derivatives thereof and pharmaceutically acceptable salts thereof exhibit excellent antibacterial activity without cross-resistance to conventional medicaments and are therefore useful as a medicament effective to prevent and treat bacterial infections, and they have accomplished the present invention.